於Si(111)-(√3×√3)/Au表面上鍍Pb所引發的重構

Pb-induced Reconstructions on Si(111)-(√3×√3)/Au Surface

梁皓鈞(HAO-CHUN LIANG)

指導教授 ： 門福國

國立中正大學/理學院/物理學系/碩士(2016年)

摘要

在Si(111)-(7×7)的表面上成長Au原子，隨著磊晶量的不同，表面形成的重構也有所不同。我們觀察到(√3×√3)重構出現於磊晶量0.5~1ML，此重構是由週期為(√3×√3)的domains與隨著磊晶量增加而更密集的domain walls所組成。
　　在實驗中，我們準備了Au磊晶量為0.75ML的(√3×√3)表面，接著磊晶0.06ML的Pb，會發現結構轉變為(2√21×2√21)的重構。根據文獻內容可知，(2√21×2√21)重構出現於Si(111)-(7×7)的表面上700℃加熱時，丟上Au原子並熱退火至室溫。當再次加熱至350℃並退火至室溫後，此結構變為(√3×√3)，即使再度加熱至700℃後退火至室溫，依舊不見(2√21×2√21)重構，因此(2√21×2√21)為亞穩定態，且轉變成(√3×√3)的過程是不可逆的。而在本實驗中，我們觀察到Pb引發(√3×√3)轉變為(2√21×2√21)，且可經由控制鍍Pb的量，彼此相互轉換。

關鍵字

Si(111) ； (√3×√3) ； (2√21×2√21)

並列摘要

By depositing Au onto a Si(111)-(7×7) surface, the surface reconstructs into different structures as Au coverage increases. We observe a (√3×√3) reconstruction by depositing 0.5~1ML of Au. This reconstruction is consisted of (√3×√3) domains separated by domain walls. The domain wall density increases with the Au coverage.
　　To do our experiment we prepare the (√3×√3) reconstruction by depositing 0.75ML of Au. Pb atoms are deposited onto this surface, which results in the formation of a (2√21×2√21) reconstruction. This (2√21×2√21) structure has been reported in the literature by depositing Au onto Si(111)-(7×7) surface at 700℃ and followed by annealing. The (2√21×2√21) reconstruction prepared by Au deposition transforms into the (√3×√3) after annealing at 350℃. It doesn’t reappear even after a second heating at 700℃ and followed by annealing. Consequently, the (2√21×2√21) reconstruction is metastable and transforms irreversibly into the (√3×√3). Here, we observe this (√3×√3) to (2√21×2√21) transition simply by depositing Pb and show that such transition is reversible.

並列關鍵字

Si(111) ； (√3×√3) ； (2√21×2√21)

參考文獻

[16]柯詠瀚, “Effect of surface conditions on the distribution of Si adatoms on Si(111)-5×2/Au surface”, 國立中正大學物理研究所碩士論文 (2015).

[8]陳建融, “Anomalous behavior of Si adatoms on Si(111)-(5×2)/Au surface”, 國立中正大學物理研究所碩士論文 (2015).

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